1,2,4-Oxadiazole derivatives having aromatic groups on the 3- and 5-positions are known as physiologically active substances in pharmaceutical and agrochemical fields. As a method of producing the derivatives, a method of reacting an acyl chloride and an aromatic N-hydroxyamidine in the presence of an aqueous base and an organic solvent incompatible with water (see, for example, Patent Document 1).
In addition, it is disclosed that thiophene-2-carboaldehyde and benzamidoxime are reacted in the presence of toluene, a molecular sieve and piperidine to obtain 3-phenyl-5-(thiophen-2-yl)-4,5-dihydro-1,2,4-oxadiazole (see, for example, Patent Document 2).